Electric stop mechanism for knitting machines



Nov. 19, 1940.

J. WACHSMAN ELECTRIC STOP MECHANISM FOR KNITTING MACHINES Filed OClZ. 5l, 1939 4 'o 0 mD- o O l Zai 79 r-J J4 7/ Zi 26- l 1| l l X/l 29/ .2b 36 31./ 22 2# Lf;

2f v/ f l im. 5- 75L 70 73 77 79 W72 Jaa/ /Vmf/zmn/ 75 /3 ,3 INVENTOR fmt WWW ATTORNEY Patented Nov. 19, 1940 UNITED STATES PATENT OFFlCE ELECTRIC STOP MECHANISM FOR KNITTING MACHINES 1 Claim.

This invention relates to improvements in electric stop mechanisms for knitting machines of the type disclosed in my U. S. Patent 1,845,455, February 16, 1932.

The object of the invention is to provide an improved type of electric stop mechanism for actuating the stop handle of the driving unit of the machine when a thread breaks or the thread runs out. More particularly it is an object of lo the invention to provide a small compact stop mechanism having but few parts, easy of manufacture and installation and inexpensive.

With these objects in View the invention is ema bodied in an electric stop mechanism arranged D and constructed as hereinafter set forth and as illustrated in the accompanying drawing in which Fig. 1 is a front view of the stop mechanism with the front cover removed to show the mechanism and parts are broken away.

Fig. 2 is an end view looking from the left in Fig. 1.

Fig. 3 is a rear view of the stop mechanism with the back cover removed and parts broken away.

Fig. 4 is a sectional view on the line 4-4 of Fig. 3.

Fig. 5 is a wiring diagram.

Referring first to Fig. 5 the numeral I0 indicates conventionally a stop handle of a driving unit in a knitting machine. When the handle is swung on its pivot I I the knitting machine stops. 'Ihe operation is similar to that of shifting a belt pulley in other machinery. In knitting machines the operation of the stop handle is controlled by the thread. That is, when the thread breaks or runs out the handle III is to be operated to stop the machine. The controlling mechanism is in the form of a switch which is normally held in circuit open position by the thread. Such switches are called end detectors or knot detectors or stop motions in the art. In Fig. 5 if, will be seen that the thread I2 runs over two guides I3, I3 and that a detector I4 rests upon the' thread. The detector I4 is merely a switch arm which, when not supported by the thread, moves down by any suitable means and contacts a switch plate I5 which is grounded. The detector is connected to a battery I6. This in turn is connected to an electromagnet I1. The other end of the coil is connected to a spring contact I8 which is grounded. It will therefore be seen that so long as the switch or detector I4 is supported by the thread the circuit is open and the electromagnet cannot attract its armature lever I9. The latter acts to hold a plunger 20 in a set position 56. against the tension of a plunger spring 2|. The

plunger is adapted to move the stop handle I3 as shown. If now the detector switch I4 closes because the thread breaks or runs out, the circuit is closed, the electromagnet is energized, the armature lever I9 is actuated to release the 5 plunger 29, the latter operated by the spring 2i in turn throws the stop handle I0 to stop the machine and the circuit is immediately open by the upward movement of the spring contact I3. Thus only for a moment is the circuit closed. 10 This is of course an advantage as it eliminates accidents due to shocks from the current. The detector switch I4 and the relation of the lever I9 and plunger 20 are shown wholly conventionally. The foregoing is a brief description of the 15 operation of a typical electric stop mechanism for knitting machines. This invention is concerned with the construction and arrangement of those parts of the mechanism whereby the plunger is held, operated and again set for the next operation.

Referring now to the other figures the plunger 20 is slidably supported in a boX 22. The latter is open at the front and at the back as a matter of convenience for assembling the parts. The front is closed by a front cover 23. The back is closed by a back plate 24. The box 22 supports the electromagnet I1 and the armature lever I9 is pivoted in the box at 25. A small spring 26 tends to keep the lever I9 open with respect to 30 the magnet. The lever has a small stop 21' which spaces the lever in open position with respect to the magnet as will be understood. One end of the magnet coil is connected outside the boX to a circuit terminal 28 of well known design. The 35 other end of the magnet coil is connected to the contact spring I8. The armature lever I9 has a small stop lip 29 which by the action of the said small spring 26 is held in position in front of and in engagement with the tail end 39 of a plunger 40 holding lever 3| which is pivoted at 32 and provided with a slot 33. The latter is engaged by a pin 34 which is carried by a setting lever 35 pivoted a1; 36. The setting lever has cam surfaces 31, 38 and two stops 39 and 49. The plung- 45 er 20 has a heavy transverse finger 4I.

The operation is as follows. In setting the mechanism for action the operator pushes the plunger to the right in Fig. 3 against the tension of the spring 2|, the linger 4I passing over the 50 cams 31 and 38 and against the stop 39 thereby moving the setting lever 35 clockwise about its pivot 36 so that the pin 34 by engagement with the slot 33 in the locking lever 3I moves the latter anticlockwise about the pivot 32 whereby to bring 5.5

the tail 3U of lever 3| down behind and in engagement with the stop lip 29 of the armature lever I9 which thus holds the locking lever 3i against movement until the magnet is energized. This action is evidenced by a clicking noise. The operator then lets go of the plunger which then by the spring 2l is pushed backwards until the finger M rests against the other stop d@ on the setting lever 35. The mechanism is now set and ready for operation. The plunger spring is cornpressed between the finger and the wall of the box and the finger has also engaged and 1depressed the spring contact I8 to ground against the box itself.

In this normal position of the parts there is a steady pressure by the plunger spring 2| upon the ringer 4| and the plunger 2B to push the plunger in the op-posite direction, tothe leftin Fig. 3. Such movement cannot however, take place until the locking lever is released, said lever preventing movement of the pin 34 and setting lever 35. When the plunger is set by the operator it is of course also brought into suitable operative connection with the stop handle i depending upon the particular location and construction thereof. Y

.When now the circuit is closed at the detector switch as described in connection with Fig. 5, the magnet is energized, the armature lever is retracted, the stop lip 29 moves away from the tail 3B of the locking lever and the latter is released. Now, by the force of the plunger spring 2l, the plunger is pushed quickly to the left in Fig. 3 and the stop handle I0 is actuated to stop the machine.

When the plunger is thus moved it swings the setting lever 35 anticlockwise about the pivot 36, the pin 34 moving upwards in the slot 33 to swing the locking lever clockwise about the pivot 32. 'Ihe blow ofthe plunger as it is operated by the plunger spring is cushioned by a cushion spring 42. away from the spring i8 the latter tips upward and breaks the circuit as explained above. The armature lever i9 is then moved away from the magnet by the spring 26 a distance measured by the small stop 21 and whereby the stop lip 29 is positioned to permit the tail 30to pass behind the same.

To sum up: The electric stop mechanism is set by the operator to compress the plunger actuating spring 2| and at the same time cause the locking lever tail 3D to be caught behind and held by the armature lever stop lip 29. The circuit is also grounded. When the circuit is Closed at the detector' switch I4 the magnet is energized, the locking lever 3i released and the plunger spring` quickly and rather forcibly actuates the plunger to operate the driving unit stop handle HI. f

When the plunger is actuated by the spring the finger il snaps over the corner of the stop tu and thus rides over thel cam surface 38 to push down the setting lever 0n the one side` of the pivot 36. This brings the other cam surface 31 do-wn into an inclined position to lbe engaged by the nger 4I when the mechanism is set by Alsoas soon as the iinger 4l moves' the operator so that the finger 4| glides easily in over the setting lever and into engagement with the stop 33 to move the pin 3a downward in the slot 33 to reset the locking lever.

The plunger 20 may have a convenient handle as at 45 in Fig. 5. In order to test the mechanism apart from the operation of the detector switches a small pin 4t is provided which is accessible from the outside for the purpose of tripping the armature leverv i9, see Figs. 1 and 4. After the mechanism has been set the operator may push the pin inward to trip the lever 29 whereupon the plunger will be actuated and the operator will know that the mechanism is in order. The magnet is attached to the box by a screw 50. In order to prevent accidental or wilful loosening Aof this screw the cover 23, Fig. 2, is provided with a, bent lip 52 which conceals the screw.

The stop mechanism according to this invention is characterized by extreme simplicity in construction and comprises relatively few parts. It is easy to manufacture and assemble and extremely efficient in operation. The box may be mounted in any convenient position to engage the stop handle il! and the plunger is readily shaped for such engagement.

I claim:

In an electric stop mechanism for power driven machines wherein is provided an electric circuit with a normally open circuit closerI controlled by the material being operated upon and which includes a stop handle; a plunger for actuating said stop handle, a linger on said plunger, a spring yfor moving the plunger in one direction, a setting lever, two stops thereon, one of said stops engagingl said plunger ngerto hold the plunger immovable against the action of said spring, a locking lever in operative engagement with said setting lever to maintain said stop Y thereon in engagement with said plunger finger, an electromagnet in said circuit, an armature for said magnet arranged to hold said locking' lever in operative engagement with the setting lever and arranged to release the locking lever when the armature is attracted by the magnet, an

automatic switch in said circuit embodying a spring memlber normally tending to automatically open said circuit, said spring member being mountedin the path of movement of said plunger ringer to engage said setting lever and arranged to be moved into circuit closing position by said nger during its said movement and maintained in circuit closing position by said finger thereafter, a second stop on the setting lever arranged to be momentarily, engaged by said plunger nger to move said setting and lock,- ing levers into normal plunger holding positions, said plunger and finger thereon being moved byv said spring into engagement with said first named setting lever stop after said setting and locking4 levers have been moved into normal plunger holding positions as aforesaid, a box through which said plunger slides, said box enclosing and supporting all of the aforesaid elements.

JACOB WACI-ISMAN. 

